Variable length catheter for drug delivery

ABSTRACT

A system and method for localized delivery of a therapeutic or diagnostic agent within a vessel is provided. The system and method provide for adjustability of the length of the treatment area and for reducing of pressure within the treatment area. A catheter system includes an inner elongated element, an outer elongated element positioned coaxially with respect to the inner elongated element, and a blood-release element at a distal end of the inner elongated element. A proximal occlusion element is positioned at the distal end of the outer elongated element, proximal to an outlet port. A distal occlusion element is positioned at a distal end of the inner elongated element. The distal end of the inner elongated element is distal to and movable with respect to the outer elongated element distal end.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application is a continuation-in-part of U.S. patentapplication Ser. No. 13/080,667, filed on Apr. 6, 2011, which is acontinuation-in-part of U.S. patent application Ser. No. 12/731,222,filed on Mar 25, 2010, now U.S. Pat. No. 8,109,897, issued on Feb. 7,2012, which is a divisional of U.S. patent application Ser. No.11/338,892,filed on Jan. 25, 2006, now U.S. Pat. No. 7,704,220, issuedon Apr. 27, 2010, all of which are incorporated by reference herein intheir entireties.

FIELD AND BACKGROUND OF THE INVENTION

The present invention relates to systems and methods for delivery oftherapeutic or diagnostic agents, wherein the systems provide forvarying lengths of the treatment area. The systems and methods hereinare designed for selective treating of an area without adverselyaffecting other parts of the body.

Methods and devices designed to provide drugs to a vessel, include, forexample, the use of drug coated balloons, such as disclosed in U.S. Pat.No. 5,954,706 to Sahatjian, for example. Such devices include a catheterwith an expandable portion, wherein at least a portion of the exteriorsurface of the expandable portion is defined by a coating of hydrogelpolymer. Incorporated within the hydrogel polymer is a solution of apreselected drug to be delivered to the tissue or plaque. Disadvantagesof such devices include the need to choose a particular drug and dosagein advance, as well as limitations on the length and diameter of thetreatment area as defined by the predetermined length and diameter ofthe expandable portion, since these devices often work by direct contactof the device to the vessel.

Another device is disclosed in U.S. Pat. No. 6,287,320 to Slepian. Acatheter includes first and second expansile members which are expandedto occlude a diseased region, and a therapeutic agent is introduced intothe diseased region via the catheter. The catheter is allowed to remainin place for a therapeutically effective amount of time to allow thetherapeutic agent to contact the diseased portion for such a period oftime.

Another device is disclosed in US Patent Publication 2007/0078433 toSchwager et al. This device includes a balloon catheter having apredetermined inflow angle of medication. A first and second balloon arepositioned on the catheter, with a treatment zone therebetween.Disadvantages of devices such as the ones disclosed in theabove-referenced publications include limitations on the length of thetreatment area as predetermined by the distance between the expansilemembers.

A device disclosed in US Patent Application Publication Number2005/0059930 to Garrison et al. includes a catheter system with at leasttwo expandable occluding elements which are used to create a localizedsite for administration of agents. The catheters are slidable withrespect to one another to vary the space between the balloons asdesired. However, the localized site is prone to overpressure sincethere is no disclosed way to remove excess fluid from the site.

There is thus a need for, and it would be highly advantageous to have, asystem and method for localized drug delivery within a vessel, withadjustability of the length of the treatment area and with means forreducing pressure buildup in the treatment zone.

SUMMARY OF THE INVENTION

There is provided, in accordance with embodiments of the presentinvention, a catheter system having an inner elongated element and anouter elongated element positioned coaxially with respect to the innerelongated element. The outer elongated element has a proximal end and adistal end, with an outer elongated element lumen extending from theproximal end to the distal end, and having an outlet port at the distalend. A proximal occlusion element is positioned at the distal end of theouter elongated element, proximal to the outlet port. The innerelongated element has a proximal end and a distal end, a blood-releaseelement at the distal end of the inner elongated element, and a distalocclusion element positioned at the distal end of the inner elongatedelement. The distal end of the inner elongated element is distal to andmovable with respect to the outer elongated element distal end. A corewire extends from the distal end to the proximal end of the innerelongated element. In accordance with further features of the presentinvention, the system may further include a treatment or diagnosticsolution positioned within the outer elongated element lumen, between anouter wall of the inner elongated element and an inner wall of the outerelongated element and between the distal and proximal occlusionelements. Buildup of pressure by introduction of the solution can beprevented by blood flow through the blood-release element. The innerelongated element may further include a guidewire therethrough. A hubmay be included at the outer elongated element proximal end, forintroduction of a therapeutic or diagnostic solution into the outerelongated element lumen, and further for introducing inflation fluid toone or both of the occlusion elements. In some embodiments, the innerelongated element is introduced into the outer elongated element via thehub. The blood-release element may be included either as a separatedistal element or as an opening within the distal occlusion element,wherein the blood-release element may be used for clearing blood out ofthe treatment zone, and additionally for introduction of a guidewiretherethrough, for rapid exchange of catheters. In one embodiment thedistal and proximal occlusion elements are inflatable balloons, andouter and inner elongated elements further comprise inflation lumens forinflating the inflatable balloons.

In accordance with further features of the present invention, the innerelongated element has an exposed portion, with an exposed portionproximal edge at a proximal occlusion element distal end, and an exposedportion distal edge at a distal occlusion element proximal end. Theexposed portion has a length extending from the exposed portion proximaledge to the exposed portion distal edge, and this length may be variedby moving the inner elongated element with respect to the outerelongated element.

In accordance with an additional embodiment of the present invention,there is provided a method for treating a vessel. The method includesintroducing an outer elongated element having a proximal occlusionelement at a distal end thereof into the vessel, introducing an innerelongated element having a distal occlusion element and a blood-releaseelement at a distal end thereof, positioning the outer elongated elementcoaxially with respect to the inner elongated element, and positioning adistal end of the inner elongated element distal to the distal end ofthe outer elongated element. The distal occlusion element ispositionable at varying distances from the proximal occlusion element.The method further includes deploying the distal and proximal occlusionelements and introducing a treatment or diagnostic solution through theouter elongated element into the vessel between the distal and proximalocclusion elements while simultaneously removing blood from the vesselvia the blood-release element.

In accordance with further features of the present invention,positioning of the outer elongated element coaxial to the innerelongated element may be done prior to introducing the outer and innerelongated elements into the vessel, or may be done during theintroducing, wherein the inner elongated element may be introducedthrough the outer elongated element lumen, for example. The introducinginto the vessel may be done by positioning the catheter over a guidewirepositioned within the outer elongated element lumen, or by placing aguidewire through a blood-release element. The distance between thedistal and proximal occlusion elements may be adjusted prior tointroducing the drug solution.

In accordance with yet an additional embodiment of the presentinvention, there is provided a system having an outer elongated elementwith an outer elongated element proximal end and an outer elongatedelement distal end, the outer elongated element having an outerelongated element lumen extending from the outer elongated elementproximal end to the outer elongated element distal end and having anoutlet port at the outer elongated element distal end, and a proximalocclusion element located at the outer elongated element distal end, theproximal occlusion element proximal to the outlet port, an innerelongated element having an inner elongated element proximal end and aninner elongated element distal end, the inner elongated element havingan inner elongated element lumen extending from the inner elongatedelement proximal end to the inner elongated element distal end, ablood-release element at the inner elongated element distal end, and adistal occlusion element located at the inner elongated element distalend. The inner elongated element is positioned within the outerelongated element lumen wherein the outer elongated element is coaxiallyarranged with respect to the inner elongated element, and wherein theinner elongated element distal end is distal to and movable with respectto the outer elongated element distal end. The system further mayinclude a supply elongated element coaxial to the outer elongatedelement, the supply elongated element having an inlet port at a distalend thereof, wherein the inlet port is proximal to the outer elongatedelement distal end.

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. Although methods and materialssimilar or equivalent to those described herein can be used in thepractice or testing of the embodiments of the present invention,suitable methods and materials are described below. In case of conflict,the patent specification, including definitions, will control. Inaddition, the materials, methods, and examples are illustrative only andnot intended to be limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is herein described, by way of example only, withreference to the accompanying drawings. With specific reference now tothe drawings in detail, it is stressed that the particulars shown are byway of example and for purposes of illustrative discussion of thepreferred embodiments of the present invention only, and are presentedin the cause of providing what is believed to be the most useful andreadily understood description of the principles and conceptual aspectsof the invention. In this regard, no attempt is made to show structuraldetails of the invention in more detail than is necessary for afundamental understanding of the invention, the description taken withthe drawings making apparent to those skilled in the art how the severalforms of the invention may be embodied in practice.

In the drawings:

FIG. 1A is an illustration of a system including a catheter and acontrol unit, in accordance with one embodiment of the presentinvention;

FIG. 1B is an illustration of a system including a catheter and acontrol unit, in accordance with another embodiment of the presentinvention;

FIG. 2 is a schematic illustration of the control unit of the systems ofFIGS. 1A and 1B;

FIG. 3 is an illustration of a catheter in accordance with anotherembodiment of the present invention;

FIGS. 4A, 4B and 4C are illustrations of several embodiments of a distalportion of the catheters of FIG. 1A, FIG. 1B and FIG. 3, having distalends which are variably positionable;

FIGS. 5A-5C are illustrations of a catheter having a bendable distalend, in accordance with one embodiment of the present invention;

FIG. 6 is an illustration of a catheter which is suitable for anchoringin a separate vessel in accordance with one embodiment of the presentinvention;

FIGS. 7A-7C are illustrations of a distal portion of a catheter which issuitable for anchoring in a separate vessel, in accordance with anotherembodiment of the present invention;

FIGS. 8A-8H are illustrations of the steps of a method of positioning acatheter in a vessel in accordance with embodiments of the presentinvention;

FIGS. 9A-9H are illustrations of the steps of a method of positioning acatheter in a vessel in accordance with additional embodiments of thepresent invention;

FIGS. 10A-10F are illustrations of the steps of a method of positioninga catheter in a vessel in accordance with yet additional embodiments ofthe present invention;

FIGS. 11A-11C are illustrations of the steps of a method for treating aspecific target site in accordance with one embodiment of the presentinvention;

FIGS. 12A-12C are illustrations of a method for treating a specifictarget site in accordance with another embodiment of the presentinvention;

FIGS. 13A-13C are illustrations of a method for treating a specifictarget site in accordance with yet another embodiment of the presentinvention;

FIGS. 14A-14D are schematic and cross-sectional illustrations of asystem in accordance with embodiments of the present invention, havingan outer elongated element with a proximal occlusion element positionedthereon, an inner elongated element with a distal occlusion elementpositioned thereon, and at least one outlet port for delivery of asolution;

FIGS. 15A-15F are schematic and cross-sectional illustrations of thesystem of FIGS. 14A-14D, further including a blood-release element, inaccordance with embodiments of the present invention;

FIG. 15G is a schematic illustration of a catheter with a fixed wireballoon, in accordance with embodiments of the present invention;

FIGS. 16A-16C are schematic illustrations of the system of FIGS.14A-14D, showing a distal end thereof in accordance with embodiments ofthe present invention;

FIGS. 17A-17F are schematic illustrations of steps of a method ofdelivering a therapeutic or diagnostic agent to a treatment area of avessel, in accordance with embodiments of the present invention;

FIGS. 18A-18D are schematic illustrations of steps of a method ofdelivering a therapeutic or diagnostic agent to a treatment area of avessel in accordance with additional embodiments of the presentinvention; and

FIGS. 19A-19F are schematic illustrations of steps of a method of usinga catheter in accordance with embodiments of the present invention forretrograde access of an artery such as a pedal artery, for example.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is of systems and methods which can be used fordelivery of a therapeutic or diagnostic agent into a vessel. For thepurposes of the present invention, the term “delivery substance” is usedto include any therapeutic or diagnostic agent which may be deliveredinto the vessel, including but not limited to medications, saline,contrast media, sealing agents, etc. The present invention can be usedto selectively adjust the length of the vessel-access delivery portionof the catheter and to control the period of exposure of the deliverysubstance at the selected location in a contained manner.

The principles and operation of systems and methods according to thepresent invention may be better understood with reference to thedrawings and accompanying descriptions.

Before explaining at least one embodiment of the invention in detail, itis to be understood that the invention is not limited in its applicationto the details of construction and the arrangement of the components setforth in the following description or illustrated in the drawings. Theinvention is capable of other embodiments or of being practiced orcarried out in various ways. Also, it is to be understood that thephraseology and terminology employed herein is for the purpose ofdescription and should not be regarded as limiting.

Reference is now made to FIGS. 14A and 14B, which are a schematicillustration and a cross-sectional illustration, respectively, of asystem 300 in accordance with embodiments of the present invention.System 300 includes a catheter 312 which includes an outer elongatedelement 320 having an outer elongated element lumen 321 therethrough andan inner elongated element 322 having an inner elongated element lumen323 therethrough. Inner elongated element 322 is preferably an elongatedtubular member, extending through an entire length of catheter 312,having an inner elongated element proximal end 316 and an innerelongated element distal end 318. In some embodiments, inner elongatedelement 322 has a guidewire exit port 324 at or near inner elongatedelement distal end 318. Guidewire exit port 324 is configured forplacement of a guidewire therethrough, as will be explained furtherhereinbelow, but can also be used for perfusion, or exchange ofdifferent sized guidewires, for example. In some embodiments, innerelongated element lumen 323 and guidewire exit port 324 are notincluded, and the profile of inner elongated element 322 may be reduced.Outer elongated element 320 is preferably an elongated tubular memberhaving an outer elongated element proximal end 325 and an outerelongated element distal end 327. Outer elongated element 320 ispositioned coaxially with respect to inner elongated element 322, asshown in cross-section A-A, in FIG. 14B, and extends from innerelongated element proximal end 316 to a location proximal to innerelongated element distal end 318.

In one embodiment, as shown in FIG. 14A, outer elongated element 320 hasan outlet port 326 located at outer elongated element distal end 327. Inthis embodiment, outlet port 326 is created by the coaxial arrangementof outer elongated element 320 and inner elongated element 322, whereinan inner diameter of outer elongated element 320 is sized at least 0.10mm (i.e. 0.004″) greater than an outer diameter of inner elongatedelement 322 and may be 3 mm (0.12″) greater or more, depending on thesize of catheter 312. The space created by this difference in diametercreates a delivery lumen 378 (depicted in FIG. 14B) which issufficiently sized for providing a delivery substance to the vessel, aswill be described in greater detail hereinbelow. A distal end ofdelivery lumen 378 is outlet port 326. Moreover, delivery lumen 378 maybe sized for placement of a guidewire therethrough, as will beexplained. In embodiments of the present invention, an outer diameter ofinner elongated element 322 is in a range of 0.02″ to 0.08 inches, andmore specifically may be in a range of 0.025-0.35″ for a smaller versionof system 300 or in a range of 0.05-0.06″ for a larger version of system300. An inner diameter of inner elongated element 322 is in a range of0.01″ to 0.05″, and more specifically may be in a range of 0.015″-0.02″for a smaller version of system 300 and 0.035″-0.045″ for a largerversion of system 300. An outer diameter of outer elongated element 320is in a range of 0.05″-0.15″, and more specifically may be in a range of0.055″-0.065″ for a smaller version of system 300 and in a range of0.115″-0.130″ for a larger version of system 300. An inner diameter ofouter elongated element 320 is in a range of 0.025″-0.1″, and morespecifically may be in a range of 0.030″-0.050″ for a smaller version ofsystem 300 and in a range of 0.080″-0.090″ for a larger version ofsystem 300. It should be readily apparent that the invention is notlimited to the dimensions listed herein and that these dimensions shouldbe taken as exemplary.

In another embodiment, as shown in FIG. 14C, outer elongated element 320has multiple outlet ports 344, which are openings within a body of outerelongated element 320, at one or more locations along its length, forproviding a delivery substance to the blood vessel. Outward movement ofdrug solution, contrast, diagnostic solution, or other substance isindicated by arrows 348. In yet another embodiment, as shown in FIG.14D, both outlet port 326 and multiple outlet ports 344 are used.

Returning now to FIG. 14A, a proximal occlusion element 328 ispositioned on outer elongated element 320 at or near outer elongatedelement distal end 327, such that proximal occlusion element 328 isproximal to outlet port 326. In the embodiments shown in FIGS. 14C and14D, proximal occlusion element 328 is positioned proximal to multipleoutlet ports 344. Proximal occlusion element 328 has a proximalocclusion element proximal end 370 and a proximal occlusion elementdistal end 372. A distal occlusion element 329 is positioned on innerelongated element 322, at or near inner elongated element distal end318, proximal to guidewire exit port 324, and distal to outer elongatedelement distal end 327. Distal occlusion element 329 has a distalocclusion element proximal end 374 and a distal occlusion element distalend 376. Inner elongated element 322 is movable with respect to outerelongated element 320. Thus, an exposed portion 350 of catheter 312 maybe defined as having an exposed portion proximal edge 351 at proximalocclusion element distal end 372 and an exposed portion distal edge 353at distal occlusion element proximal end 374. Exposed portion 350 has alength L extending from exposed portion proximal edge 351 to exposedportion distal edge 353, and length L may be varied by moving innerelongated element 322 with respect to outer elongated element 322.

Inner elongated element lumen 323 may be configured to hold a guidewiretherein, and outer elongated element lumen 321 is configured to holdinner elongated element 322 therein and to further hold a deliverysubstance in between an outer wall of inner elongated element 322 and aninner wall of outer elongated element 320 within delivery lumen 378. Insome embodiments, outer elongated element lumen 321 is furtherconfigured to hold a guidewire therein. The delivery substance may beintroduced into the vessel through outlet port 326 and/or multipleoutlet ports 344, but is prevented from flowing outside of a treatmentzone by inflation of proximal occlusion element 328 and inflation ofdistal occlusion element 329. Thus, a length of the treatment zone inthe vessel is determined by length L of exposed portion 350.

A hub 330 is positioned at a proximal end of catheter 312 and isattached to outer elongated element 320 at outer elongated elementproximal end 325. Hub 330 includes an infusion port 340 for introducinga delivery substance such as a drug solution into delivery lumen 378(i.e. outer elongated element lumen 321) and a proximal occlusionelement inflation port 342 for delivery of inflation fluid to proximalocclusion element 328. Hub 330 may further include a pressure monitoringvalve 346.

Referring now to FIG. 14B, the configuration of outer elongated element320 and inner elongated element 322 in accordance with embodiments ofthe present invention is shown in cross-section. Outer elongated elementlumen 321 is configured to receive therein both inner elongated element322 and a delivery substance introduced via infusion port 340. Outerelongated element 320 may further include an inflation lumen 380 forintroducing inflation fluid into proximal occlusion element 328, and apressure lumen 382. The pressure lumen has a proximal pressuretransducer attached thereto which is capable of measuring the pressureof a column of fluid located within the pressure lumen. Outer elongatedelement lumen 321 may also be configured to receive a guidewiretherethrough, in between the body of outer elongated element 320 andinner elongated element 322. Inner elongated element 322 may have aninner elongated element lumen 323 for receiving a guidewiretherethrough, and further includes a distal inflation lumen forintroducing inflation fluid into distal occlusion element 329. A corewire 336 is positioned within or attached to inner elongated element322. In some embodiments, core wire 336 is positioned between layers ofa polymer shaft of inner elongated element 322.

In some embodiments, outer elongated element 320 is advanced into avessel first with a guidewire positioned through outer elongated elementlumen 321, followed by inner elongated element 322 which may be advancedthrough outer elongated element lumen 321 of outer elongated element320, resulting in the guidewire and inner elongated element 322positioned side by side within outer elongated element lumen 321. Inother embodiments, outer elongated element 320 and inner elongatedelement 322 are advanced together into the vessel. The introduction ofsystem 300 with outer elongated element 320 and inner elongated element322 may be done either as an over the wire system, wherein a guidewireis introduced into the vessel and then positioned within inner elongatedelement lumen 323, whereupon system 300 is advanced over the guidewire,or may be done using a blood-release element on inner elongated element322, as will be described below with reference to FIGS. 15A-15F.

Reference is now made to FIG. 3, which is an illustration of a catheter312 in accordance with another embodiment of the present invention.Catheter 312 is similar in construction to catheter 312 shown in FIGS.14A-14D, with an additional feature of a supply elongated element 20positioned coaxial to inner and outer elongated elements 322 and 320.

In one embodiment, supply elongated element 20 has inlet ports at one ormore locations along its length for receiving blood from the bloodvessel. In a preferred embodiment, as shown in FIG. 3, supply elongatedelement 20 has an inlet port 26 located at a distal end 21 thereof. Inthis embodiment, inlet port 26 is created by the coaxial arrangement ofsupply elongated element 20 and outer elongated element 320, wherein aninner diameter of supply elongated element 20 is sized at least 0.1 mmgreater than an outer diameter of outer elongated element 320. The spacecreated by this difference in diameter creates a port which issufficiently sized for receiving supply blood from the vessel, as willbe described in greater detail hereinbelow.

Hub 330 may connect supply elongated element 20 and inner elongatedelement 322 to a control unit, as described hereinbelow with referenceto FIG. 2. The control unit may thermally alter (i.e. heat or cool)normothermic blood received from supply elongated element 20, and sendthe thermally altered blood out through inner elongated element 322.Blood received from supply elongated element 20 may be treated oraltered in other ways as well, or may simply be used to perfuse thevessel distal to distal occlusion element 329.

In one embodiment, supply elongated element 20 is a standard vascularsheath and may have a side arm 27 from which blood is removed from thevessel and potentially sent to a control unit. In another embodiment,supply elongated element 20 is an extended sheath, and may extend to 100cm or more depending on the application.

Reference is now made to FIGS. 15A-15F, which are schematicillustrations (FIGS. 15A and 15D) and cross-sectional illustrations(FIGS. 15B, 15C, 15E and 15F), respectively, of inner elongated element322 with a blood-release element 338 in accordance with embodiments ofthe present invention. Blood-release element 338 may also be used forplacement therethrough of a movable guidewire 332. Blood-release element338 is sized with a diameter slightly larger than a diameter of movableguidewire 332. For example, an inner diameter of blood-release element338 may be approximately 0.002″ greater than a diameter of movableguidewire 332. This difference in diameter provides a clearance spacefor controlled removal of blood from the treatment zone, which can beuseful in preventing pressure buildup in the treatment zone when thedelivery substance is introduced. If sized correctly, deliverysubstance, such as contrast solution, should not be able to leak throughthe clearance space due to its viscosity being higher than that ofblood.

In one embodiment, as shown in FIGS. 15A-15C, blood-release element 338comprises an opening 334 at distal occlusion element proximal end 374.Movable guidewire 332 may be introduced into catheter 312 at innerelongated element distal end 318 through inner elongated element lumen323 and exiting at opening 334 located at or near distal occlusionelement proximal end 374. In another embodiment, as shown in FIGS.15D-15F, blood-release element 338 comprises a separate distal element342 positioned on inner elongated element 322 distal to distal occlusionelement 329. In some embodiments, blood-release element 338 has a lengthof 4-20 cm. Blood-release element 338 allows for rapid exchange ofcatheters and for removal of blood from the treatment zone. Innerelongated element 322 further includes a core wire 336 positioned forproviding stiffness through catheter 312. This enhances pushability ofcatheter 312. Core wire 336 is positioned within inner elongated element322 and may be attached to distal occlusion element 329 at a distal endthereof and to proximal end 316 of inner elongated element 322. Corewire 336 may further be attached at additional points along the lengthof inner elongated element 322. In some embodiments, core wire 336 issandwiched between polymeric layers of a shaft of inner elongatedelement 322.

For the embodiments shown in FIGS. 15A-15F wherein a blood-releaseelement is used with movable guidewire 332, outer elongated elementlumen 321 may house movable guidewire 332 when inner elongated element322 and outer elongated element 320 are positioned coaxially to oneanother. In these embodiments, inner elongated element 322 and outerelongated element 320 may be initially positioned coaxial to oneanother, and movable guidewire 332 is introduced through blood-releaseelement 338 of inner elongated element 322. Catheter 312, having bothinner and outer elongated elements 322 and 320, is advanced over movableguidewire 332. Once movable guidewire 332 is positioned withinblood-release element 338, it is further positioned in between an outersurface of inner elongated element 322 and an inner surface of outerelongated element 320—that is, within outer elongated element lumen 321.This allows for an over the wire type of advancement, but with a reducedprofile, since an additional over the wire lumen is not required. Inthis case, inner elongated element lumen 323 may be eliminated thusreducing the profile of catheter 312. Alternatively, inner elongatedelement lumen 323 may be used for other items. For example, a mandrelmay be introduced through inner elongated element lumen 323 forenhancing pushability and for advancing inner elongated element 322. Insome embodiments, inner elongated element lumen 323 may be used forexchanging guidewires, or for putting a second guidewire in the vessel.Alternatively, inner elongated element lumen 323 may be used forperfusion. For example, in a case of prolonged occlusion while treatingthe vessel, blood may be introduced through inner elongated elementlumen 323 to an area distal to distal occlusion element 329, thus makingit possible to keep treating the vessel for as long as necessary. Thismay be particularly useful in the coronary arteries, for example, whichcannot be occluded for a prolonged period of time. In some embodiments,blood may be cooled or otherwise treated and then introduced throughinner elongated element lumen 323. In some embodiments, a supply elementis included as well, as described with reference to FIG. 3, for removingblood from the vessel which may then be reintroduced through innerelongated element lumen 323. In some embodiments, inner elongatedelement 322 may be removed from outer elongated element 320 during aprocedure.

Reference is now made to 15G, which is an illustration of a catheter 312in accordance with yet another embodiment. In this embodiment, insteadof blood-release element 338, a fixed wire 341 is used. Thus, forexample, distal occlusion element 329 may be a fixed wire balloon. Insome embodiments, an additional movable wire may be introduced throughouter elongated element lumen 321. In yet another embodiment, ablood-release element 338 and a fixed wire 341 are used, andblood-release element 338 is sized for blood to pass through but not forthe drug solution

Reference is now made to FIGS. 16A-16C, which are illustrations of adistal portion of catheter 312, in accordance with embodiments of thepresent invention, wherein distal occlusion element 329 is positionableat varying distances from proximal occlusion element 328. It should benoted that FIGS. 16A-16C are variations of FIGS. 4A-4C, described infurther detail hereinbelow. Inner elongated element 322 is movablewithin outer elongated element 320. Movement can be a twisting motion,for example, wherein inner elongated element 322 and outer elongatedelement 320 are attached with a bellows 56, as shown in FIG. 16A.Alternatively, movement can be a sliding motion, wherein inner elongatedelement 322 and outer elongated element 320 are attached via telescopingmeans 58, as shown in FIG. 16B. In a preferred embodiment, movement isachieved by coaxial arrangement of outer elongated element 320 and innerelongated element 322, as shown in FIG. 16C. In this arrangement, it maybe necessary to include an adjustable anchor 63 for anchoring theproximal portion of inner elongated element 322 to the body or surgicaldrape of the patient. Alternatively, a length of outer elongated element320 may protrude proximal to the proximal end of catheter 312. In thiscase, it may be necessary to include an adjustable anchor for anchoringthe proximal portion of outer elongated element 320 to the body orsurgical drape of the patient. Any suitable adjustable anchor means maybe used, including, for example, a luer lock, a gland, a squeeze-lockmechanism, etc. Any other means for changing a distance between distalocclusion element 329 and proximal occlusion element 328 or betweendistal end 318 of inner elongated element 322 and distal end 327 ofouter elongated element 320 is included within the scope of theinvention.

In embodiments of the present invention, radiopaque markers 48 may beincluded on distal occlusion element 329, proximal occlusion element 328and other locations along catheter 312 for visualization of the positionof catheter 312 within the vessel and relative positions of distal andproximal occlusion elements 329 and 328.

Reference is now made to FIGS. 17A-17F, which are schematicillustrations showing a method of using catheter 312.

A vessel 200 is shown with a lesion 202. As shown in FIG. 17A, movableguidewire 332 is introduced into vessel 200 adjacent lesion 202. Asshown in FIG. 17B, outer elongated element 320 is introduced overmovable guidewire 332, and is positioned proximal to lesion 202. Next,as shown in FIG. 17C, proximal occlusion element 328 is inflated. In analternative embodiment, proximal occlusion element 328 is inflated lateron in the procedure, after inner elongated element 322 is in place.Next, as shown in FIG. 17D, inner elongated element 322 is introducedthrough outer 321 lumen of outer elongated element 320 and is positioneddistal to lesion 202. Next, as shown in FIG. 17E, distal occlusionelement 329 is inflated, thus defining a treatment area T betweeninflated proximal occlusion element 328 and inflated distal occlusionelement 329. Next, as shown in FIG. 17F, a delivery substance, such as adrug solution, is introduced into treatment area T via outer elongatedelement lumen 321 of outer elongated element 320. It should be readilyapparent that treatment area T may be adjusted by introducing innerelongated element 322 at varying distances from a distal end of outerelongated element 320. Alternatively or in addition to the embodimentsshown herein, outer elongated element 320 may have one or multipleoutlet ports 326, 344 as described with reference to FIGS. 14C and 14D.In some embodiments, the delivery substance may also be removed fromvessel 200 through outlet port 326. In some embodiments, the method mayinclude a repeatable cycle of introducing the delivery substance,removing the delivery substance, deflating distal and proximal occlusionelements, reestablishing blood flow, reinflating distal and proximalocclusion elements, and reintroducing the same or a different deliverysubstance. This cyclic introduction and removal of the deliverysubstance is possible since the delivery substance can remain insideouter elongated element 320, and distal and proximal occlusion elementsmay be inflated and deflated. This method can provide a benefit ofprolonged drug exposure without prolonged stoppage of blood flow. Insome embodiments, inner elongated element 322 may be removed from vessel200 during the procedure, and a different catheter may be introducedthrough outer elongated element 320 for additional procedures.

Reference is now made to FIGS. 18A-18D, which are schematicillustrations showing a method of using catheter 312 in accordance withadditional embodiments of the present invention. A vessel 200 is shownwith a lesion 202. As shown in FIG. 18A, movable guidewire 332 isintroduced into vessel 200 adjacent lesion 202. Next, as shown in FIG.18B, catheter 312 having inner elongated element 322 positioned withinouter elongated element 320, is introduced over movable guidewire 332 byplacing movable guidewire 332 through blood-release element 338 on innerelongated element 322. Movable guidewire 332 is further positionedproximally through outer elongated element lumen 321 of outer elongatedelement 320. Next, as shown in FIG. 18C, proximal occlusion element 328is inflated, and inner elongated element 322 is adjusted, as shown byarrows 350, such that distal occlusion element 329 is positioned distalto lesion 202. Once inner elongated element 322 is in position, distalocclusion element 329 may be inflated, as shown in FIG. 18D. Blood maybe allowed to leak out through blood-release element 338, as depicted byarrows 380, and a delivery substance, such as a drug solution, isintroduced through outer elongated element lumen 321 of outer elongatedelement 320 through outlet port 326 and/or through multiple outlet ports344 (not shown). Alternatively, the sequence of balloon inflation may bevaried. For example, distal occlusion element 329 may be inflated first,followed by proximal occlusion element 328. It should be readilyapparent that a feature of the present invention is the flexibility ininflating and/or deflating the occlusion elements as necessary. In someembodiments, the delivery substance may also be removed from vessel 200through outlet port 326. In some embodiments, the method may include arepeatable cycle of introducing the delivery substance, removing thedelivery substance, deflating distal and proximal occlusion elements,reestablishing blood flow, reinflating distal and proximal occlusionelements, and reintroducing the same or a different delivery substance.This cyclic introduction and removal of the delivery substance ispossible since the delivery substance can remain inside outer elongatedelement 320, and distal and proximal occlusion elements may be inflatedand deflated. This method can provide a benefit of prolonged drugexposure without prolonged stoppage of blood flow. In some embodiments,inner elongated element 322 may be removed from vessel 200 during theprocedure, and a different catheter may be introduced through outerelongated element 320 for additional procedures.

Reference is now made to FIGS. 19A-19F, which are schematicillustrations of a method of using catheter 312 for retrograde access ofan artery such as a pedal artery, for example. In this embodiment,distal occlusion element 329 is a compliant balloon. As shown in FIG.19A, first a retrograde guidewire 400 is advanced into a vessel 200having an occlusion 202. Retrograde guidewire 400 is introduced intovessel 200 from a retrograde direction, via a hollow needle, forexample. Next, a guidewire 332 is advanced into vessel 200 from anantegrade direction, as shown in FIG. 19B. Next, catheter 312 havingdistal occlusion element 329 on inner elongated element 322 is advancedover guidewire 332. In some embodiments, guidewire 332 is positionedthrough a lumen of inner elongated element 322. In other embodiments,guidewire 332 is positioned through a blood-release element, asdescribed in embodiments of the present invention. In other embodiments,guidewire 332 is positioned through outer elongated element lumen 321.As described above, a delivery substance may be introduced throughoutlet ports 326, 344 during any point in the advancement of catheter312 into vessel 200. When catheter 312 is in place on the antegrade sideof occlusion 202, guidewire 332 is removed from catheter 312, and distalocclusion element 329 is expanded, as shown in FIG. 19D. Next, as shownin FIG. 19E, inner elongated element 322 (or all of catheter 312) ispulled back proximally, shown by arrows 442, and due to the compliantproperty of distal occlusion element 329, distal occlusion element 329forms a funnel shape within the vessel 200 and/or within the occlusion202. Next, as shown in FIG. 19F, retrograde guidewire 400 may beadvanced through occlusion 202 and into inner elongated element 322 ofcatheter 312. Because of the funnel-shape of distal occlusion element329, it is relatively easy to find the opening in inner elongatedelement 322. Retrograde guidewire 400 may be comprised of a flexiblematerial and/or design (e.g. coil springs) so as not to puncture distalocclusion element 329. It should be readily apparent that guidewire 332may alternatively be removed from catheter 312 just before advancementof retrograde guidewire 400. Once retrograde guidewire 400 is incatheter 312, retrograde guidewire 400 may be advanced proximallythrough catheter 312, and then used to replace guidewire 332 for theprocedure to follow.

In alternative embodiments, a system is presented for use in deliveringthermally treated blood to a location in the body.

Referring now to the drawings, FIGS. 1A and 1B illustrate a system 10for selective cooling or heating of an organ, in accordance withpreferred embodiments of the present invention. System 10 includes acatheter 12 and a control unit 14. Catheter 12 has a proximal end 16 anda distal end 18, and includes a supply elongated element 20 having asupply lumen 120 therethrough and a delivery elongated element 22 havinga delivery lumen 122 therethrough. Delivery elongated element 22 ispreferably an elongated tubular member, extending through an entirelength of catheter 12, from proximal end 16 to distal end 18, and has anexit port 24 at or near distal end 18 for delivery of blood to a targetsite. Supply elongated element 20 is preferably an elongated tubularmember which is positioned coaxially with respect to delivery elongatedelement 22, as shown in cross-section A-A, and extends from proximal end16 of catheter 12 to an area proximal to distal end 18. In analternative embodiment, supply elongated element 20 runs alongsidedelivery elongated element 22. In one embodiment, as shown in FIG. 1A,supply elongated element 20 has inlet ports 26 at one or more locationsalong its length, for receiving normothermic blood from the bloodvessel. In a preferred embodiment, as shown in FIG. 1B, supply elongatedelement 20 has an inlet port 26 located at a distal end 21 thereof. Inthis embodiment, inlet port 26 is created by the coaxial arrangement ofsupply elongated element 20 and delivery elongated element 22, whereinan inner diameter of supply elongated element 20 is sized at least 0.1mm greater than an outer diameter of delivery elongated element 22. Thespace created by this difference in diameter creates a port which issufficiently sized for receiving supply blood from the vessel, as willbe described in greater detail hereinbelow. In a preferred embodiment,an outer diameter of delivery elongated element 22 is in a range of0.081 inches to 0.128 inches and an inner diameter of supply elongatedelement 20 is in a range of 0.100 inches to 0.162 inches.

As shown in FIGS. 1A and 1B, at least one occlusion element 28 ispositioned at or near distal end 18 of catheter 12, proximal to exitport 24 and distal to a distal end 21 of supply elongated element 20. Ahub 30 for connecting supply elongated element 20 and delivery elongatedelement 22 to control unit 14 is located at proximal end 16 of catheter12. Hub 30 includes an inlet connector 32 for providing supply blood toa supply blood inlet 34 in control unit 14, and an outlet connector 36for receiving delivery blood from a delivery blood outlet 38 in controlunit 14. Control unit 14 thermally alters (i.e. heats or cools)normothermic blood received from supply blood inlet 34, and sends thethermally altered blood out through delivery blood outlet 38. Catheter12 can be introduced over a guidewire, either as an over-the-wire systemor as a rapid exchange system, or may include a fixed wire at its distaltip. In a preferred embodiment, delivery elongated element 22 acts as aguidewire lumen as well. In alternative embodiments, a separateguidewire lumen is positioned alongside or coaxial with deliveryelongated element 22. In the fixed-wire configuration, catheter 12 couldfurther include a torqueable catheter shaft. In one embodiment, such asthe one depicted in FIG. 1B, delivery elongated element 22 and supplyelongated element 20 are detachable from and/or movable with respect toone another.

The general cycle of blood flow is as follows. Normothermic blood,depicted by unbroken arrows 44, flows from a blood vessel, through atleast one inlet port 26, and into supply elongated element 20. Supplyelongated element 20 delivers the normothermic blood to control unit 14via inlet connector 32. Blood is then thermally altered in control unit14. Delivery elongated element 22 receives thermally altered blood,depicted by broken arrows 46, from delivery blood outlet 38 in controlunit 14 via outlet connector 36, and delivers the thermally alteredblood to the target site in the body. In order to ensure that heating orcooling of the target site is accomplished without causing heating orcooling of other parts of the body, it is necessary to physicallyseparate the collection of normothermic blood from the delivery ofthermally altered blood. In order to accomplish this separation using asingle device, catheter 12 is designed with both a supply elongatedelement and a delivery elongated element having an occlusion element 28for separation of blood inflow and outflow. By placing occlusion element28 between distal end 21 of supply elongated element 20 and exit port24, only the blood proximal to occlusion element 28 enters supply lumen120, and the thermally altered blood only reaches that part of thearterial system which is distal to occlusion element 28.

Reference is now made to FIG. 2, which is a schematic illustration ofcontrol unit 14 in greater detail. Control unit 14 includes supply bloodinlet 34 for receiving normothermic blood, depicted by unbroken arrow44, and delivery blood outlet 38 for delivering thermally altered blood,depicted by broken arrow 46. Control unit 14 further includes a thermaladjustor 40 for changing a temperature of normothermic blood receivedfrom supply blood inlet 34, thus producing thermally altered blood.Thermal adjustor 40 can be a heating mechanism, a cooling mechanism, ora combination heating/cooling mechanism which is controllable by a user.In a preferred embodiment, thermal adjustor 40 is a cooling mechanismsuch as, for example, Medtronic, Inc.'s Bio-Cal® Blood TemperatureControl Module or the MYOthermXP® Cardioplegia System. Alternatively,thermal adjustor 40 comprises a coiled tubing in an ice bath. In apreferred embodiment, control unit 14 further includes a pumpingmechanism 42 to facilitate delivery of thermally altered blood throughdelivery blood outlet 38. Pumping mechanism 42 can be, for example, acentrifugal blood pump (Bio-Pump®, Medtronic, Inc.; Sarns™CentrifugalSystem, Terumo Cardiovascular Systems) or an electromagnetic pump(Levitronix® CentriMag® Blood Pumping System, Levitronix GmbH). In oneembodiment, control unit 14 further comprises a vacuum to assist inwithdrawal of the normothermic blood.

In order to more closely monitor physiological parameters during aprocedure, sensors 50 may be placed at or near exit port 24, shownschematically in FIGS. 1A and 1B. Sensors 50 can include one or severalsensors, capable of measuring pressure, temperature, flow, or acombination thereof. In an alternative embodiment, pressure is measuredby providing an additional lumen referred to as a pressure lumen. Thepressure lumen has a proximal pressure transducer attached thereto whichis capable of measuring the pressure of a column of fluid located withinthe pressure lumen. Sensors 50 are in communication with control unit 14via conventional wires 51 or via wireless communication. As shown inFIG. 2, control unit 14 can further include a processor 53 for receivingand processing signals from sensors 50 and providing an output based onthe processed signals. Output can be sent to a display 57, whichprovides output information to a user. The user can make a decisionbased on this output information regarding further adjustments of thetemperature, flow and pressure. Display 57 can be, for example, avisual, audio, numeric or any other suitable display. When a user seesthe display, he/she can manually adjust thermal adjustor 40. The usercan also decide to immediately stop the procedure if necessary.Alternatively, processor 53 sends output directly to thermal adjustor40, which then automatically changes cooling or heating parameters basedon the output.

In one embodiment, hub 30 further includes an infusion port 52, as shownin FIGS. 1A and 1B. Infusion port 52 can be used, for example, tointroduce contrast media to the site. Alternatively, infusion port 52can be used to introduce drugs. For example, lytic agents which aretypically used to dissolve clots can be introduced via infusion port 52into an artery, rather than the common practice of intravenous deliveryof these agents. Alternatively, in some circumstances it may bedesirable to introduce clotting agents, which can be done via infusionport 52. It should be readily apparent that any suitable agent,compound, drug, or substance can be introduced via infusion port 52, andall of these possibilities are included within the scope of the presentinvention.

Occlusion element 28 is comprised of an atraumatic surface so as not todamage the inner walls of a blood vessel. In a preferred embodiment,occlusion element 28 has a hydrophilic surface, which by attractingwater forms a natural atraumatic layer. Furthermore, a hydrophilicsurface can provide means for occlusion which is configured to open whenin contact with water components from the blood. Occlusion element 28may further include a coating for providing long-term (measured inhours, days or even months) implantation of catheter 12 in the body.Alternatively or in addition, occlusion element 28 may further include adrug coating. In one embodiment, occlusion element 28 is a balloon, suchas is commonly used with catheter systems, and is expandable byintroduction of a fluid therein, wherein the fluid can be a liquid or agas. In this embodiment, a separate inflation lumen is included withincatheter 12, either alongside or coaxial with delivery elongated element22, and is in fluid communication with occlusion element 28. Fluid isintroduced via an inflation port (not shown) positioned at hub 30. Thesetypes of balloons and inflation lumens are commonly known in the art.The balloon may be elastomeric, compliant, semi-compliant ornon-compliant, as long as it serves to occlude the vessel withoutcausing damage to the internal walls. In one embodiment, the balloon ispre-formed and relatively thin, so as to reduce the pressure necessaryto inflate the balloon, while keeping the outer diameter to a minimum.For example, balloon thickness may range from 0.0001 inches to 0.001inches, a range which is smaller than thicknesses of standard occlusionballoons.

In another embodiment, occlusion element 28 is a self-expanding elementconfined within a retractable sheath, such that upon retraction of thesheath, the self expanding element expands to a diameter sufficient toocclude the vessel. In this embodiment, the sheath is connected to aretractor positioned at proximal end 16 of catheter 12. Theself-expanding element may be comprised of an elastic or spring-likematerial, or a shape-memory alloy. Such materials are known in the art.In another embodiment, occlusion element 28 is a mechanically actuatedmechanism, whereby it is expanded by mechanical means. In yet anotherembodiment, occlusion element 28 is comprised of a temperature sensitivematerial which can be expanded or retracted by exposure to specifictemperatures. Specifically, perfusion of cooled or heated blood throughdelivery lumen 122 would cause expansion of occlusion element 28, andperfusion of normothermic blood through delivery lumen 122 (such as, forexample, during renormalization of temperature) would cause retractionof occlusion element 28. This may be accomplished, for example, by usinga shape-memory material, either as occlusion element 28 itself, or as anactuator positioned alongside occlusion element 28. Similarly, thiscould be accomplished by using a bi-metallic strip. In one embodiment,occlusion element 28 is an integral part of the catheter, wherein aportion of catheter 12 having a slightly wider diameter is configured tobe wedged into the vessel, and thus acts as occlusion element 28,providing both occlusion and anchoring functionality.

Occlusion element 28 further includes a radiopaque marker 48 for viewingof a location of catheter 12 generally and occlusion element 28specifically within the vessel. In one embodiment, occlusion element 28is itself comprised of radiopaque material. In alternative embodiments,one or more radiopaque markers 48 are positioned on occlusion element28. Additional radiopaque markers 48 may also be positioned in otherplaces along catheter 12 such as, for example, at distal end 18, or atinlet ports 26. In one embodiment, a radiopaque marker 48 is positionedat the distal tip of catheter 12. Radiopaque marker 48 can be a ringsurrounding the distal tip, or, in order to minimize stiffness at thetip, a radiopaque marker 49 (shown in FIG. 1B) may be comprised of asmall sliver of radiopaque material embedded within a portion of thedistal tip. In one embodiment, radiopaque marker 48 is filled with anadhesive and positioned so as to seal an inflation lumen for inflationof occlusion element 28.

Reference is now made to FIG. 3, which is an illustration of a catheter12 in accordance with another embodiment of the present invention.Catheter 12 is similar in construction to catheter 12 shown in FIGS. 1Aand 1B, with an additional feature of an auxiliary delivery elongatedelement 23, preferably situated between supply elongated element 20 anddelivery elongated element 22. Auxiliary delivery elongated element 23is preferably an elongated tubular member having an auxiliary lumen 123therethrough, and is configured to receive a supplemental blood flowfrom control unit 14 (shown in FIGS. 1A and 1B) and to deliver thesupplemental blood (depicted by wide arrows 47) to a vessel. In oneembodiment, the supplemental blood is taken from the control unit 14 andintroduced into auxiliary delivery elongated element 23 at an initialthermally altered temperature. Supplemental blood as depicted by widearrows 47 undergoes a temperature change during its flow from theproximal end to the distal end of auxiliary delivery elongated elementdue to conduction from the normothermic blood in the blood vessel whichis in close proximity thereto. In this embodiment, the temperature ofsupplemental blood that exits ports 25 of auxiliary delivery elongatedelement 23 is of a different temperature T₂ than the temperature T₁ ofthe thermally altered blood depicted by broken arrows 46, which isdelivered to the target site. The presence of an additional layer ofblood flow in a lumen surrounding delivery elongated element 22 providesincreased insulation for the thermally altered blood being delivered tothe target site. Furthermore, blood from auxiliary delivery elongatedelement 23 can be used for simultaneous treatment of different parts ofthe body. Thus, for example, if it were desired to treat the target sitewith one temperature and an additional site with another temperature,auxiliary delivery elongated element 23 could be used for treatment ofthe additional site. The amount of temperature change that occurs withinauxiliary delivery lumen 123 depends on the flow rate and the initialtemperature difference between the thermally altered blood enteringauxiliary delivery lumen 123 and the normothermic blood surroundingauxiliary delivery elongated element 23.

In a preferred embodiment, auxiliary delivery elongated element 23 iscoaxially arranged with respect to delivery elongated element 22, andincludes at least one secondary exit port 25, preferably in a distalportion thereof. In an alternative embodiment, exit port 25 isconfigured similar to inlet port 26 as depicted in FIG. 1B, wherein anexit port 25 is created by the coaxial arrangement of auxiliary deliveryelongated element 23 and delivery elongated element 22, wherein an innerdiameter of auxiliary delivery elongated element 23 is sized at least0.1 mm greater than an outer diameter of delivery elongated element 22.The space created by this difference in diameter is sufficient fordelivering supply blood to the vessel. The distal portion of auxiliarydelivery elongated element 23 is proximal to exit port 24. Supplyelongated element 20 is positioned coaxially with respect to auxiliarydelivery elongated element 23, and distal end 21 of supply elongatedelement 20 is proximal to secondary exit ports 25. In one embodiment,supply elongated element 20 is a standard vascular sheath and may have aside arm 27 from which normothermic blood is sent to control unit 14. Inanother embodiment, supply elongated element 20 is an extended sheath,and may extend to 100 cm or more depending on the application.

A second occlusion element 54 may be positioned proximal to secondaryexit ports 25 and distal to inlet ports 26 of supply elongated element20. In this way, a first target site is supplied by thermally alteredblood exiting delivery elongated element 22 and having a temperature T₁,and a second target site is separately supplied by supplemental bloodexiting auxiliary delivery elongated element 23 and having a temperatureT₂.

Reference is now made to FIGS. 4A-4C, which are illustrations of adistal portion of catheter 12, in accordance with another embodiment ofthe present invention, wherein exit port 24 is positionable at varyingdistances from ports 61. Ports 61 are inlet or outlet ports of a coaxialelongated element 60, which can be any elongated element coaxial todelivery elongated element 22. In one embodiment, coaxial elongatedelement 60 is a supply elongated element and ports 61 are inlet ports.In another embodiment, coaxial elongated element 60 is an auxiliarydelivery elongated element, and ports 61 are secondary exit ports.Delivery elongated element 22 is movable within coaxial elongatedelement 60. Movement can be a twisting motion, for example, whereindelivery elongated element 22 and coaxial elongated element 60 areattached with a bellows 56, as shown in FIG. 4A. Alternatively, movementcan be a sliding motion, wherein delivery elongated element 22 andcoaxial elongated element 60 are attached via telescoping means 58, asshown in FIG. 4B. In a preferred embodiment, movement is achieved bycoaxial arrangement of coaxial elongated element 60 and deliveryelongated element 22, as shown in FIG. 4C. In this arrangement, deliveryelongated element 22 can be variably positioned within coaxial elongatedelement 20. Thus, a length of delivery elongated element 22 may protrudeproximal to the proximal end of catheter 12. In this case, it may benecessary to include an adjustable anchor 63 for anchoring the proximalportion of delivery elongated element 22 to the body or surgical drapeof the patient. Alternatively, a length of supply elongated element 20may protrude proximal to the proximal end of catheter 12. In this case,it may be necessary to include an adjustable anchor for anchoring theproximal portion of supply elongated element 20 to the body or surgicaldrape of the patient. These configurations allow for the tip of catheter12 to be positioned as desired, without concern for the resultinglocation of the proximal end. Any suitable adjustable anchor means maybe used, including, for example, a luer lock, a gland, a squeeze-lockmechanism, etc. Any other means for changing a distance between exitport 24 and ports 61 is included within the scope of the invention.

In some instances, it may be desirable to anchor catheter 12 into avessel, providing greater control and easier accessibility to the targetsite. Reference is now made to FIGS. 5A-5C, which are illustrations of acatheter having a bendable distal end 18 for anchoring. As shown in FIG.5A, catheter 12 includes delivery elongated element 22 and occlusionelement 28. At least one exit port 24 is located distal to occlusionelement 28. In one embodiment, exit port 24 is at distal end 18 ofcatheter 12. In another embodiment, exit port 24 is located anywherebetween occlusion element 28 and distal end 18. In one embodiment,distal end 18 is initially in a straightened positioned as it isadvanced over a guidewire 62. Guidewire 62 is insertable throughdelivery lumen 122. Alternatively, guidewire 62 may be insertablethrough a separate guidewire lumen (not shown), which is either coaxialwith or adjacent to delivery lumen 122. Catheter 12 is advanced overguidewire 62 until a desired location is reached. Guidewire 62 is thenremoved, allowing catheter 12 to assume a bent configuration, asdepicted in FIG. 5B. The bent configuration is suitable for anchoring ina vessel, as shown schematically in FIG. 5C. In an alternativeembodiment, catheter 12 has a fixed wire at its distal end, and distalend 18 is initially straightened by inserting a removable stylet. Oncethe desired location is reached, the stylet is removed, causing distalend 18 to assume its bent configuration. In one embodiment, distal end18 is comprised of a shape memory alloy.

Alternatively, it may be desirable to anchor catheter 12 in a vesselother than the one leading to the target site. For example, if catheter12 is anchored in a branch vessel, thermally altered blood can bediverted into the main vessel by strategically placing exit port 24 at aspecific location or locations.

Reference is now made to FIG. 6, which is an illustration of catheter 12suitable for anchoring in a separate vessel, in accordance with oneembodiment of the present invention. Catheter 12 has a closed distal end18 and an exit port 24 located along its shaft, proximal to distal end18. Catheter 12 further includes at least two occlusion elements: firstocclusion element 28, which is positioned between exit port 24 and ports61 of coaxial elongated element 60, and distal occlusion element 55,which is positioned between exit port 24 and distal end 18 of catheter12. Coaxial elongated element 60 and ports 61 can be supply elongatedelement 20 with inlet ports 26, or auxiliary delivery elongated element23 and secondary exit ports 25. First occlusion element 28 is designedto separate an area for receiving thermally altered blood (i.e. thetarget site) from an area supplying normothermic blood to control unit14, or from an area receiving supplemental blood at a differenttemperature T₂. Distal occlusion element 55 is designed to act as ananchor, while also separating an area for receiving thermally alteredblood (the target site) from an untreated area. In a preferredembodiment, first and distal occlusion elements 28 and 55 includeradiopaque markers 48 for allowing for positioning of catheter 12 withinthe blood vessel.

Reference is now made to FIGS. 7A and 7B, which are illustrations of adistal portion of catheter 12, suitable for anchoring in a separatevessel, in accordance with another embodiment of the present invention.As shown in FIG. 7A, guidewire 62 is introducible through deliveryelongated element 22. In an alternative embodiment, catheter 12 includesa separate guidewire elongated element (not shown) either coaxial withor alongside delivery elongated element 22. Catheter 12 includes adistal occlusion element 55, which in one embodiment is an inflatableballoon designed to extend over distal end 18 upon inflation. As shownin FIG. 7B, inflation of distal occlusion element 55 results inexpansion of the balloon over distal end 18, causing the delivery lumento be sealed. This type of configuration can be accomplished, forexample, by attaching the balloon to the catheter shaft near the distalend of the catheter, such that upon inflation, the balloon is configuredto expand over the edge of catheter 12. Alternatively, distal occlusionelement 55 can have multiple attachment points 57, as shown in FIG. 7Cin a deflated state, which dictate a direction of expansion for distalocclusion element 55. Exit port 24 is located on the shaft of catheter12, and is positioned proximal to distal occlusion element 55.

It should be readily apparent that in all of the described embodiments,additional lumens may be included for various purposes. For example, alumen for oxygenation of blood may be added. Additional cooling/heatinglumens or additional lumens to control flow or pressure may be added aswell.

In a preferred embodiment, system 10 is used to provide hypothermia fortreatment of stroke. A target temperature for cooling is in the range of18 to 30 degrees Celsius, and may be maintained for hours or days. Thesystem described herein also allows for gradual rewarming of the treatedarea by slowly introducing blood of different temperatures.

Introduction and positioning of catheter 12 into a selected vessel inthe body can be accomplished in various ways. Reference is now made toFIGS. 8A-8H, which are schematic illustrations of a method ofpositioning catheter 12 in a selected vessel in the body. In theembodiment shown, catheter 12 is positioned in the left internal carotidartery. However, it should be readily apparent that catheter 12 mayalternatively be positioned in the right or left common carotidarteries, or any of the internal or external carotid arteries based onthe target location. Initially, an incision or puncture is made at aperipheral location, typically the femoral artery, although otherlocations such as the brachial or radial artery, for example, can beused as well. A guidewire 162 is inserted through the incision and intothe vessel, in this case, femoral artery 200, as shown in FIG. 8A.Optionally, as shown in FIG. 8B, a vascular sheath 202 with a dilatorportion is introduced over guidewire 162. Vascular sheaths and dilatorsare commonly known in the art, and are commonly used for providingvascular access to catheters. Once the sheath is in place, the dilatoris removed, and a search catheter 204 is introduced over guidewire 162,as shown in FIG. 8C. Search catheter 204 can be, for example, a guidingcatheter or an angiography catheter, both of which are types ofcatheters known in the art, and which include a tip which is pre-shapedin various configurations, suitable for selecting particular vessels.While search catheter 204 is positioned over guidewire 162, the tip ofsearch catheter 204 is relatively straight. Search catheter 204 andguidewire 162 are advanced together through arterial system and into theaortic arch 210, as shown in FIG. 8D. Guidewire 162 is pulled backproximally, which allows for search catheter 204 to assume its bentconfiguration, suitable for selecting a specific vessel. Search catheter204 is then used to locate the left common carotid artery 212, as shownin FIG. 8E. Search catheter 204 may alternatively be used to locate theright common carotid artery 214. Guidewire 162 is then advanced intoleft common carotid artery 212, as shown in FIG. 8F. Search catheter 204is removed, and guidewire 162 may be advanced further into the leftinternal carotid artery 218, as shown in FIG. 8G. Alternatively,guidewire 162 may be advanced into an external carotid artery 216, ormay remain in the common carotid artery 212, depending on the targetedarea. Catheter 12 of the present invention is then introduced overguidewire 162, with the tip of delivery elongated element 22 positionedwithin the selected vessel, in this case left internal carotid artery218 as shown in FIG. 8H. Supply elongated element 20 preferably remainswithin aortic arch 210. This method can be used for a catheter 12 inaccordance with any of the described embodiments above.

Reference is now made to FIGS. 9A-9H, which are schematic illustrationsof the steps of an alternative method of introduction and positioning ofcatheter 12 into a selected vessel in the body. In this method, anincision or puncture is made as described above, and a long guidewire164 is introduced into the vessel, in this case, femoral artery 200, asshown in FIG. 9A. Supply elongated element 20, which in at least oneembodiment described above (see for example, FIG. 1B) is detachable fromthe rest of catheter 12, is introduced over guidewire 164, as shown inFIG. 9B. A removable dilator 166 is positioned within supply elongatedelement 20 to facilitate percutaneous introduction. Supply elongatedelement 20 is advanced, either with the removable dilator in place orafter the removable dilator has been removed, until supply elongatedelement 20 is in a position within aortic arch 210 proximal to the leftcommon carotid artery 212, as shown in FIG. 9C. If the dilator had notpreviously been removed, at this point the dilator is removed. Searchcatheter 204 is then introduced through supply elongated element 20, asshown in FIG. 9D. Guidewire 164 is pulled back proximally, which allowsfor search catheter 204 to assume its bent configuration, suitable forselecting a specific vessel. Search catheter 204 is then used to locatethe left common carotid artery 212, as shown in FIG. 9E. Search catheter204 may alternatively be used to locate the right common carotid artery214. Guidewire 164 is then advanced into left common carotid artery 212,as shown in FIG. 9F. Search catheter 204 is removed, and guidewire 164may be advanced further into the left external carotid artery 216, asshown in FIG. 9G. Alternatively, guidewire 164 may be advanced into aninternal carotid artery 218, or may remain in the common carotid artery212, depending on the desired target. Remaining portions of catheter 12which are not yet in the vessel are then introduced over guidewire 164,with the tip of delivery elongated element 22 positioned within theselected vessel, in this case left external carotid artery 216. Supplyelongated element 20 preferably remains within aortic arch 210. Thislast step creates assembly of catheter 12 within the desired location.

Reference is now made to FIGS. 10A-10F which are schematic illustrationsof the steps of an alternative method of introduction and positioning ofcatheter 12 into a selected vessel in the body. In this embodiment, anincision or puncture is made as described above, and a long guidewire164 is introduced into the vessel, as shown in FIG. 10A. A dilator 168is positioned within delivery elongated element 22, and catheter 12 withdilator 168 in place is advanced over guidewire 164, as shown in FIG.10B. Catheter 12 and dilator 168 are advanced over guidewire 164 intoaortic arch 210, as shown in FIG. 10C. When catheter 12 is in positionin aortic arch 210, dilator 168 is removed, and a search catheter 224may then be introduced though delivery elongated element 22, as shown inFIG. 10D. Search catheter 224 is sized to fit within delivery elongatedelement 22. Alternatively, delivery elongated element 22 may itself beconfigured with a bent configuration for selecting a vessel, and thusmay be used as a search catheter. Guidewire 164 is pulled backproximally, and search catheter 224 or bent delivery elongated element22 is used to locate the left common carotid artery 212, as shown inFIG. 10E. Search catheter 224 or bent delivery elongated element 22 mayalternatively be used to locate the right common carotid artery 214.Guidewire 164 is then advanced into left common carotid artery 212, asshown in FIG. 10F. Search catheter 224 is removed, and guidewire 164 maybe advanced further into the left external carotid artery 216.Alternatively, guidewire 164 may be advanced into an internal carotidartery 218, or may remain in the common carotid artery 212, depending onthe targeted area of the brain. Catheter 12 is advanced into left commoncarotid artery 212, with the tip of delivery elongated element 22positioned within the selected vessel, in this case left externalcarotid artery 216. Supply elongated element 20 preferably remainswithin aortic arch 210. For this embodiment, it may be necessary forsupply elongated element 20 to have a tapered distal end so as to avoiddamage of the vessel during insertion. If inlet ports are positionedalong supply elongated element 20, as in FIG. 1A, the distal end 21 ofsupply elongated element 20 can be tapered by design. If inlet port 26is located at the distal end 21 of supply elongated element 20, as shownin FIG. 1B, a temporary tapering element can be included at distal end21. For example, an inflatable balloon may be positioned at distal end21 of supply elongated element 20, so that during insertion, the ballooncan be inflated, providing a tapered edge, and during collection ofsupply blood, the balloon can be deflated for blood collection.

In all of the described embodiments, positioning of supply elongatedelement 20 within the vessel should be such that supply blood iscollected from retrograde flow of blood. Thus, it is preferable not toadvance the supply elongated element 20 into the common carotid artery.Rather, supply elongated element 20 (or at least the inlet ports 26 fromsupply elongated element 20) should remain in the aorta. If supplyelongated element 20 and delivery elongated element 22 are notdetachable from one another, supply elongated element 20 may be sized(lengthwise) so as to avoid its entry into the carotid artery.Alternatively, if supply elongated element 20 and delivery elongatedelement 22 are detachable, a marker on the distal end of supplyelongated element 20 may aid in this positioning. In alternativeembodiments, catheter 12 may be placed in other locations in the bodydepending on the desired target area. For example, a renal artery can betargeted to provide cooling/heating to a kidney, or a coronary arterycan be targeted to provide cooling/heating to a heart.

Reference is now made to FIGS. 11A-C, which are illustrations of amethod for treating a specific target site in accordance with apreferred embodiment of the present invention. As shown in FIG. 11A,catheter 12 is inserted into a blood vessel, and advanced to a vesselwhich is in fluid communication with the target site, referred tohereinafter as adjacent vessel 100. In a preferred embodiment, whereinthe goal is to selectively cool the brain without induction of systemichypothermia, the target site is the brain, and vessel 100 is the carotidartery (right or left, common, internal or external). A position ofcatheter 12 within vessel 100 is monitored by visualization ofradiopaque marker 48. When catheter 12 is in the desired location,occlusion element 28 is expanded, as shown in FIG. 11B. This expansionprimarily serves to isolate a particular section of adjacent vessel 100which leads to the target site, thereby preventing normothermal bloodfrom flowing into the target organ, and can also help anchor catheter 12in place. Reference is now made to FIG. 11C, which illustrates the flowof blood. Once occlusion element 28 is deployed, normothermic blood,represented by arrows 44, enters supply elongated element 20 via inletports 26. It should be readily apparent that although the methoddepicted in FIGS. 11A-11C shows supply elongated element 20 havingmultiple inlet ports and positioned in a vessel in such a way so as tocollect antegrade blood, these depictions should not be regarded aslimiting. In alternative embodiments, as described above with referenceto FIGS. 1B, 8H and 9H, supply elongated element 20 may have one inletport, and it may be positioned within the aortic arch. Normothermicblood flows through supply lumen 120, out through inlet connector 32 ofhub 30 and through supply blood inlet 34 into control unit 14. Controlunit 14 then heats or cools the blood to form thermally altered blood,which is pumped out through delivery blood outlet 38, through outletconnector 36, and into delivery elongated element 22. Thermally alteredblood, represented by broken arrow 46, flows out through exit port 24and into the portion of the blood vessel which leads to the target site.In one embodiment, pharmaceuticals are simultaneously administered tothe target site via drug infusion port 52. In another embodiment,sensors located at or near the exit ports measure physiologicalparameters such as pressure, flow and temperature, and the data is sentto control unit 14. Control unit 14 compares the received data todesired settings and adjusts heating/cooling as required. This cycle cancontinue for as long as is necessary for the particular application. Ina preferred embodiment, the cycle is repeated for 1-72 hours.

Reference is now made to FIGS. 12A-C, which are illustrations of amethod for treating a specific target site in accordance with anotherembodiment of the present invention. As shown in FIG. 12A, catheter 12is inserted into a blood vessel, and advanced to a vessel which is influid communication with the target site, referred to hereinafter asadjacent vessel 100. In a preferred embodiment, wherein the goal is toselectively cool the brain without induction of systemic hypothermia,the target site is the brain, and vessel 100 is the carotid artery(right or left, common, internal or external). A position of catheter 12within vessel 100 is monitored by visualization of radiopaque marker 48.When catheter 12 is in the desired location, occlusion element 28 andsecond occlusion element 54 are both expanded, as shown in FIG. 12B.Occlusion element 28 and second occlusion element 54 can be sequentiallyor simultaneously expanded. Expansion of occlusion element 28 primarilyserves to isolate a particular section of blood vessel 100 which leadsto the target site, and can also help anchor catheter 12 in place.Expansion of second occlusion element 54 serves to separate an area fordelivery of supplemental blood, which is of a different temperature T₂than a temperature T₁ of thermally treated blood sent to the targetsite, and from normothermic blood returning through supply elongatedelement 20. Reference is now made to FIG. 12C, which illustrates theflow of blood. Once occlusion element 28 and second occlusion element 54are deployed, normothermic blood, represented by arrows 44, enterssupply elongated element 20 via inlet ports 26. It should be readilyapparent that although the method depicted in FIGS. 12A-12C shows supplyelongated element 20 having multiple inlet ports and positioned in avessel in such a way so as to collect antegrade blood, these depictionsshould not be regarded as limiting. In alternative embodiments, asdescribed above with reference to FIGS. 1B, 8H and 9H, supply elongatedelement 20 may have one inlet port, and it may be positioned within theaortic arch. Normothermic blood flows through supply lumen 120, outthrough inlet connector 32 of hub 30 and through supply blood inlet 34into control unit 14. Control unit 14 then heats or cools the blood toform thermally altered blood, which is pumped out through delivery bloodoutlet 38, through outlet connector 36 and into delivery elongatedelement 22. Thermally altered blood, represented by broken arrow 46,flows out through exit port 24 and into the portion of the blood vesselwhich leads to the target site. In addition, supplemental blood,represented by wide arrows 47, is sent through auxiliary deliveryelongated element 23 and into a secondary vessel 101, which may lead toa secondary target site. In one embodiment, pharmaceuticals aresimultaneously administered to the target site and/or to thesupplemental blood via drug infusion port 52. In another embodiment,sensors located at or near the exit ports measure physiologicalparameters such as pressure, flow and temperature, and the data is sentto control unit 14. Control unit 14 compares the received data todesired settings and adjusts heating/cooling as required. This cycle cancontinue for as long as is necessary for the particular application.

Reference is now made to FIGS. 13A-C, which are illustrations of amethod for treating a specific target site in accordance with yetanother embodiment of the present invention. As shown in FIG. 13A,catheter 12 is inserted into a blood vessel, and advanced to a secondaryvessel 101 which is near vessel 100. For example, vessel 100 andsecondary vessel 101 can be branches of a main vessel. This method maybe desirable, for example, if vessel 100 is diseased and might beadversely affected by introduction of a foreign element such as acatheter therein. In a preferred embodiment, wherein the goal is toselectively cool the brain without induction of systemic hypothermia,the target site is the brain, and secondary vessel 101 is the carotidartery (right or left, common, internal or external). A position ofcatheter 12 within vessel 101 is monitored by radiopaque marker 48. Whencatheter 12 is in the desired location, occlusion element 28 and distalocclusion element 55 are expanded, as shown in FIG. 13B. Expansion ofocclusion elements 28 and 55 serves to isolate blood vessel 100 whichleads to the target site, and anchors catheter 12 in place withoutplacing catheter 12 directly in blood vessel 100. Reference is now madeto FIG. 13C, which illustrates the flow of blood. Once occlusionelements 28 and 55 are deployed, normothermic blood, represented byarrows 44, enters supply elongated element 20 via inlet ports 26. Itshould be readily apparent that although the method depicted in FIGS.12A-12C shows supply elongated element 20 having multiple inlet portsand positioned in a vessel in such a way so as to collect antegradeblood, these depictions should not be regarded as limiting. Inalternative embodiments, as described above with reference to FIGS. 1B,8H and 9H, supply elongated element 20 may have one inlet port, and itmay be positioned within the aortic arch. Normothermic blood flowsthrough supply lumen 120, out through inlet connector 32 of hub 30 andthrough supply blood inlet 34 into control unit 14. Control unit 14 thenheats or cools the blood to form thermally altered blood, which ispumped out through delivery blood outlet 38, through outlet connector36, and into delivery elongated element 22. Thermally altered blood,represented by broken arrow 46, flows out through exit port 24 and intothe portion of the blood vessel which leads to the target site. In oneembodiment, pharmaceuticals are simultaneously administered to thetarget site via drug infusion port. In another embodiment, sensorslocated at or near the exit ports measure physiological parameters suchas pressure, flow and temperature, and the data is sent to control unit14. Control unit 14 compares the received data to desired settings andadjusts heating/cooling as required. This cycle can continue for as longas is necessary for the particular application.

It should be readily apparent that a single catheter serves to bothcollect and deliver the normothermic and thermally altered blood. In anadditional embodiment, all or some blood contact surfaces can be coatedwith an anti thrombotic substance such as heparin.

It is appreciated that certain features of the invention, which are, forclarity, described in the context of separate embodiments, may also beprovided in combination in a single embodiment. Conversely, variousfeatures of the invention, which are, for brevity, described in thecontext of a single embodiment, may also be provided separately or inany suitable subcombination.

Although the invention has been described in conjunction with specificembodiments thereof, it is evident that many alternatives, modificationsand variations will be apparent to those skilled in the art.Accordingly, it is intended to embrace all such alternatives,modifications and variations that fall within the spirit and broad scopeof the appended claims. All publications, patents and patentapplications mentioned in this specification are herein incorporated intheir entirety by reference into the specification, to the same extentas if each individual publication, patent or patent application wasspecifically and individually indicated to be incorporated herein byreference. In addition, citation or identification of any reference inthis application shall not be construed as an admission that suchreference is available as prior art to the present invention.

What is claimed is:
 1. A catheter system comprising: an outer elongatedelement having an outer elongated element proximal end and an outerelongated element distal end, said outer elongated element having anouter elongated element lumen extending from said outer elongatedelement proximal end to said outer elongated element distal end andhaving an outlet port at said outer elongated element distal end, and aproximal occlusion element located at said outer elongated elementdistal end, said proximal occlusion element proximal to said outletport; an inner elongated element having an inner elongated elementproximal end and an inner elongated element distal end, and a distalocclusion element located at said inner elongated element distal end,said inner elongated element positioned within said outer elongatedelement lumen wherein said outer elongated element is coaxially arrangedwith respect to said inner elongated element, said coaxial arrangementproviding a delivery lumen between said inner and outer elongatedelements for delivery of a substance to a vessel through said deliverylumen and through said outlet port, wherein said inner elongated elementdistal end is distal to and movable with respect to said outer elongatedelement distal end, and wherein said inner elongated element furthercomprises a blood-release element at said inner elongated element distalend; and a guidewire positioned through said blood-release element,wherein when said guidewire is positioned through said blood-releaseelement, said blood-release element remains at least partially open toblood-flow.
 2. The catheter system of claim 1 wherein said innerelongated element further comprises a core wire extending from andattached to said inner elongated element distal end and extending to andattached to said inner elongated element proximal end.
 3. The cathetersystem of claim 2, wherein said core wire is sandwiched betweenpolymeric layers of a shaft of said inner elongated element.
 4. Thecatheter system of claim 1, wherein said inner elongated element isremovable from said outer elongated element during a procedure.
 5. Thecatheter system of claim 1, wherein said inner elongated elementcomprises an inner elongated element lumen extending from said innerelongated element proximal end to said inner elongated element distalend.
 6. The catheter system of claim 5 wherein said guidewire is furtherpositioned within said inner elongated element lumen.
 7. The cathetersystem of claim 1, wherein said substance is a therapeutic or diagnosticagent introduced into said outer elongated element lumen, and positionedbetween an outer wall of said inner elongated element and an inner wallof said outer elongated element, and positioned between said distal andproximal occlusion elements when introduced into a vessel.
 8. Thecatheter system of claim 1, further comprising a hub at said outerelongated element proximal end, said hub configured for introducing adelivery substance into said outer elongated element lumen.
 9. Thecatheter system of claim 8, wherein said hub is further configured forintroducing inflation fluid to said proximal occlusion element.
 10. Thecatheter system of claim 8, wherein said hub is further configured forintroducing said inner elongated element through said outer elongatedelement lumen.
 11. The catheter system of claim 1, wherein saidblood-release element has an inner diameter which is approximately0.002″ greater than a diameter of said guidewire.
 12. The cathetersystem of claim 1, wherein said blood-release element comprises aseparate distal element positioned distal to said distal occlusionelement.
 13. The catheter system of claim 1, wherein said blood-releaseelement comprises an opening at a proximal end of said distal occlusionelement, said opening providing an outlet for blood-flow in asubstantially axial direction.
 14. The catheter system of claim 1,wherein said blood-release element comprises a separate element having aproximal end, a distal end, and a lumen therein, said lumen extendingfrom proximal end to distal end of said distal occlusion element. 15.The catheter system of claim 1, wherein said distal occlusion element isa fixed wire balloon.
 16. The catheter system of claim 1, furthercomprising a guidewire positioned through said outer elongated element.17. The catheter system of claim 1, wherein said inner elongated elementcomprises an exposed portion having an exposed portion proximal edge ata proximal occlusion element distal end and an exposed portion distaledge at a distal occlusion element proximal end, and wherein saidexposed portion has a length extending from said exposed portionproximal edge to said exposed portion distal edge, wherein said lengthmay be varied by moving said inner elongated element with respect toouter elongated element.
 18. The catheter system of claim 1, whereinsaid outlet port comprises multiple outlet ports.
 19. The cathetersystem of claim 1, wherein said outlet port is created by the coaxialarrangement of said outer and inner elongated elements.